# PhysicStuff > Interactive physics education platform. 62 articles covering 12 subjects, with 50 browser-based interactive simulations powered by Plotly.js and Three.js. ## What this site is PhysicStuff (physicstuff.com) explains physics concepts through interactive simulations and clear writing. Articles target a general audience — starting with intuition and analogies, then moving to the underlying mathematics. All simulations run client-side in the browser with no sign-up required. ## Key pages - [Homepage](https://physicstuff.com/): Featured articles and site overview - [PhysicsLab](https://physicstuff.com/lab): Filterable gallery of all interactive simulations - [All Posts](https://physicstuff.com/posts): Full article index - [About](https://physicstuff.com/about): About the author ## Content index ### Mechanics - [Conservation of Angular Momentum: Ice Skater Spin and Gyroscope Precession](https://physicstuff.com/mechanics/conservation-of-angular-momentum): Conservation of angular momentum, L = Iω, with interactive simulators: see why a skater spins faster with arms tucked and why a spinning gyroscope precesses. - [Work-Energy Theorem and Power Calculator: From Variable Force to Watts](https://physicstuff.com/mechanics/work-energy-theorem-power): Work-energy theorem calculator — drag a force curve to compute W = ∫F dx, verify W_net = ΔKE, then explore instantaneous vs average power P = Fv. - [Torque Calculator and Rotational Motion Simulator](https://physicstuff.com/mechanics/torque-rotational-motion): Torque calculator and rotational motion simulator — balance a lever with the τ = rF sinθ formula, then race a disk, ring and sphere down a ramp. - [Conservation of Momentum: Elastic and Inelastic Collision Simulator](https://physicstuff.com/mechanics/conservation-of-momentum): Conservation of momentum explained with an interactive elastic and inelastic collision simulator — final velocity formulas, worked examples and FAQs. - [Centripetal Force Calculator and Circular Motion Simulator](https://physicstuff.com/mechanics/centripetal-force-calculator): Centripetal force calculator and circular motion simulator — compute F = mv²/r, period and acceleration, and see why the force points to the centre. - [Projectile Motion Simulator](https://physicstuff.com/mechanics/projectile-motion): Interactive projectile motion calculator — adjust launch angle, velocity, and gravity to trace live parabolic trajectories. - [Kinetic and Potential Energy Visualiser](https://physicstuff.com/mechanics/energy-visualiser): Watch kinetic and potential energy trade off as a mass descends a ramp — see conservation of energy in action with adjustable mass, height, and friction. - [Coupled Oscillators](https://physicstuff.com/mechanics/coupled-oscillators): Watch energy slosh between two spring-coupled masses and discover normal modes — the symmetric and antisymmetric oscillations that underpin everything from molecular vibrations to phonons in crystals. - [Newton's Laws of Motion](https://physicstuff.com/mechanics/newtons-laws-interactive): Explore all three of Newton's laws interactively — inertia, F = ma, and action-reaction — with live graphs and adjustable parameters. - [Simple Harmonic Motion Simulator](https://physicstuff.com/mechanics/simple-harmonic-motion): Visualise displacement, velocity, and acceleration in a spring-mass system. Adjust spring constant, mass, amplitude, and damping — explore the phase portrait. ### Chaos - [Lorenz Attractor](https://physicstuff.com/chaos/lorenz-attractor): Explore the butterfly effect with this iconic chaotic system. ### Waves & Oscillations - [Standing Waves and Resonance: Why Everything Has a Natural Frequency](https://physicstuff.com/waves-oscillations/standing-waves-resonance): Standing waves and resonance, explained interactively — build string harmonics, paint Chladni patterns with sound, and shake buildings in an earthquake sim. - [How Do Filters Work? Low-Pass and High-Pass Filters Explained](https://physicstuff.com/waves-oscillations/low-pass-high-pass-filters): Explore how low-pass and high-pass filters work with an interactive simulation — from RC circuits and cutoff frequencies to Butterworth filter design. - [Fourier Synthesis](https://physicstuff.com/waves-oscillations/fourier-synthesis): Build complex waveforms from harmonics — stack sine waves to construct square, sawtooth, and triangle waves and see how Fourier series works in real time. - [Lissajous Figures](https://physicstuff.com/waves-oscillations/lissajous-figures): Explore Lissajous figures — beautiful parametric curves traced by two perpendicular harmonic oscillators. Adjust frequency ratio and phase to see patterns shift from lines to ellipses to knots. - [Wave Packets](https://physicstuff.com/waves-oscillations/wave-packets): Explore quantum wave packets — see how superposing plane waves creates a localised particle, and discover Heisenberg's uncertainty principle through the interactive dispersion and group velocity controls. - [Wave Speed Calculator — Frequency, Wavelength and the Wave Equation](https://physicstuff.com/waves-oscillations/wave-speed-frequency-wavelength): Wave speed calculator for the wave equation — three interactive simulations show why frequency never changes speed, and how long a wavelength really is. - [The Doppler Effect](https://physicstuff.com/waves-oscillations/doppler-effect): Why does an ambulance siren drop in pitch as it passes you? Visualise the Doppler effect — wavefront compression ahead of a moving source, rarefaction behind it — with adjustable source speed and interactive spectral shifts. - [Signal Recovery with FFT](https://physicstuff.com/waves-oscillations/fft-denoising): Build a noisy signal from multiple frequencies, then use the Fast Fourier Transform to recover the original — see denoising in action. ### Electromagnetism - [Electric Potential Calculator: Equipotential Lines and Work Done Moving a Charge](https://physicstuff.com/electromagnetism/electric-potential-calculator): Electric potential calculator with interactive equipotential lines — drag point charges, compute V = kq/r, and measure the work done moving a test charge. - [Capacitors and RC Circuits: Charging, Discharging and the Time Constant](https://physicstuff.com/electromagnetism/capacitors-rc-circuits): RC circuit calculator for charging and discharging capacitors — find the time constant, series/parallel capacitance, and energy stored in a capacitor. - [Magnetic Force on a Moving Charge: The Right-Hand Rule Explained](https://physicstuff.com/electromagnetism/magnetic-force-right-hand-rule): Right-hand rule and magnetic force calculator — explore how force direction flips with a vector simulator, build a velocity selector, and separate isotopes. - [Faraday's Law: How Electromagnetic Induction Generates Electricity](https://physicstuff.com/electromagnetism/faraday-law-electromagnetic-induction): Faraday's law and Lenz's law explained with three simulators — swing a magnet through a coil, spin an AC generator, and find induced current direction. - [Equivalent Resistance Calculator: Series and Parallel Circuits](https://physicstuff.com/electromagnetism/series-parallel-circuits): Equivalent resistance calculator for series and parallel circuits — combine resistors, break a bulb string, and build a live voltage divider. - [Electric Field: Definition, Formula and Interactive Field Line Simulator](https://physicstuff.com/electromagnetism/electric-field): Electric field explained with interactive simulators — visualise field lines from point charges, apply E = kq/r² and superposition, and read field maps. - [Ohm's Law Calculator](https://physicstuff.com/electromagnetism/ohms-law): Interactive Ohm's Law calculator — enter any two of voltage, current, or resistance and compute the third, with a live V–I characteristic graph. - [Coulomb's Law Calculator — Electric Force Between Charges](https://physicstuff.com/electromagnetism/coulombs-law): Coulomb's law calculator with two interactive simulators — drag charges to trace the inverse-square force curve, and balance charged pendulums against gravity. - [How Does Lightning Occur?](https://physicstuff.com/electromagnetism/lightning): Charge separation in thunderclouds and the physics of lightning and thunder. - [How Do Magnets Work?](https://physicstuff.com/electromagnetism/magnets): Ferromagnetism, domains, and why only certain elements are magnetic. - [What is a P-N Junction?](https://physicstuff.com/electromagnetism/pn-junction): The fundamental building block of diodes, transistors, solar cells, and LEDs. - [How Do Solar Cells Work?](https://physicstuff.com/electromagnetism/solar-cells): Photovoltaic cells, band gaps, and tandem configurations — sunlight to electricity. ### Statistical Mechanics - [Maxwell Velocity Distribution](https://physicstuff.com/statistical-mechanics/maxwell-velocity): Visualize the Maxwell-Boltzmann speed distribution — see how molecular speeds shift with temperature, and compare most probable, mean, and root-mean-square velocities in an interactive simulation. ### Thermodynamics - [Ideal Gas Law Calculator: PV = nRT and Kinetic Theory Explained](https://physicstuff.com/thermodynamics/ideal-gas-law-kinetic-theory): Ideal gas law calculator with an interactive kinetic theory simulator — find pressure, volume or temperature from PV = nRT and watch molecules respond live. - [Leidenfrost Effect](https://physicstuff.com/thermodynamics/leidenfrost-effect): Why do water droplets levitate and skitter on a very hot pan? Explore the Leidenfrost effect — the vapour cushion that insulates droplets above the Leidenfrost point — with an interactive heat transfer simulation. - [What is the Triple Point? Where Water Boils and Freezes at Once — and Why Dry Ice Never Melts](https://physicstuff.com/thermodynamics/triple-point): The triple point of water — 273.16 K at 611.657 Pa, where ice, liquid and vapour coexist. Interactive phase diagram, freeze-drying and dry ice simulations. - [The Anomalous Expansion of Water: Why Ice Floats and Lakes Freeze From the Top Down](https://physicstuff.com/thermodynamics/anomalous-expansion-water): The anomalous expansion of water explained: density peaks at 4°C, ice floats, lakes freeze top-down. Drop parcels, freeze a lake, save a pipe — 3 sims. ### Mathematics & Statistics - [Statistics Fundamentals](https://physicstuff.com/mathematics-statistics/statistics-fundamentals): Interactive exploration of mean, median, mode, distributions, and confidence intervals. - [Mandelbrot Set](https://physicstuff.com/mathematics-statistics/mandelbrot-set): Zoom into the Mandelbrot set — the most famous fractal in mathematics. Explore infinite boundary complexity generated by a single recursive formula, and discover how iteration count maps to the vivid colour gradient. ### Astrophysics - [Newton's Law of Gravitation and Orbital Velocity Calculator](https://physicstuff.com/astrophysics/gravitation-orbital-mechanics): Newton's law of gravitation calculator and orbital velocity simulator — find orbital speed, period via Kepler's third law, and explore elliptical orbits. - [What Are Shooting Stars?](https://physicstuff.com/astrophysics/shooting-stars): Meteoroids, meteors, and meteorites — space rocks burning up in Earth's atmosphere. - [What is a Lunar Eclipse?](https://physicstuff.com/astrophysics/lunar-eclipse): Penumbral, partial, and total eclipses — plus the rare Super Blue Blood Moon. - [Stellar Distances](https://physicstuff.com/astrophysics/stellar-distances): How astronomers measure cosmic distances — parallax, Cepheids, and Hubble's Law. ### Optics - [Myopia and Hypermetropia: Corrective Lens Power Calculator for the Human Eye](https://physicstuff.com/optics/human-eye-myopia-hypermetropia): Myopia and hypermetropia calculator — see whether an image forms in front of or behind the retina, then find the exact corrective lens power in diopters. - [Mirror Formula Calculator: Concave and Convex Mirror Ray Diagrams](https://physicstuff.com/optics/mirror-formula-ray-diagrams): Mirror formula calculator for concave and convex mirrors — find image distance, magnification, and image type from an interactive ray diagram tool. - [Snell's Law Calculator: Refraction and Total Internal Reflection](https://physicstuff.com/optics/snells-law): Snell's law calculator and interactive refraction simulator — find the angle of refraction and critical angle, and see total internal reflection live. - [Interference and Diffraction of Light: Why Waves Make Patterns](https://physicstuff.com/optics/interference-and-diffraction): See how light waves interfere and diffract with four interactive simulations — Young's double slit, single-slit diffraction, and diffraction gratings explained. - [Lens Formula Calculator: Ray Diagrams and Chromatic Aberration](https://physicstuff.com/optics/lens-formula): Lens formula calculator with five worked examples and the full sign convention — plus a film-plane bench for chromatic aberration and achromatic doublets. - [What is a Mirage? Inferior vs Superior Mirages and Fata Morgana Explained](https://physicstuff.com/optics/mirage): What is a mirage and are mirages real? How inferior mirages, superior mirages and Fata Morgana form — explore all types with 3 interactive simulations. - [How Do 3D Glasses Work? Polarized, Anaglyph and Shutter Glasses Explained](https://physicstuff.com/optics/3d-glasses): How do 3D glasses work? Polarized, red-cyan anaglyph and active shutter glasses explained with interactive polarization and depth simulations. ### General - [What is Graphene?](https://physicstuff.com/general/graphene): A single atom thick, stronger than steel, and a better conductor than copper. - [Classical vs Quantum Computers](https://physicstuff.com/general/quantum-vs-classical): Bits vs qubits — superposition, entanglement, and the future of computing. - [Nobel Prize in Physics 2018](https://physicstuff.com/general/nobel-prize-2018): Optical tweezers and chirped pulse amplification — tools that transformed science. - [Giordano Bruno: A Born Rebel](https://physicstuff.com/general/giordano-bruno): The monk who argued the universe was infinite — and was burned at the stake for it. - [Why Redefine Mass?](https://physicstuff.com/general/redefine-mass): From a platinum cylinder in Paris to Planck's constant — the new kilogram. - [How Did Google Get Its Name?](https://physicstuff.com/general/google-name-origin): A googol, a typo, and a nine-year-old — the origin of the world's biggest search engine. ### Modern Physics - [How Does an Atomic Clock Work?](https://physicstuff.com/modern-physics/how-does-an-atomic-clock-work): How does an atomic clock work? Cesium-133's 9,192,631,770 Hz hyperfine transition locks the SI second, with laser cooling and precision explained. - [Bohr Model Calculator and Hydrogen Emission Spectrum Simulator](https://physicstuff.com/modern-physics/bohr-model-atomic-structure): Bohr model calculator for hydrogen electron energy levels — find transition wavelengths, explore the emission spectrum, and see why orbits are quantized. - [Time Dilation Calculator: Why Does Time Slow Down at High Speed?](https://physicstuff.com/modern-physics/time-dilation-special-relativity): Time dilation calculator with an animated light clock, real-world speed presets, and a spacetime diagram that resolves the classic twin paradox. - [Half-Life Calculator and Radioactive Decay Simulator](https://physicstuff.com/modern-physics/half-life-calculator): Half-life calculator with an interactive radioactive decay simulator — find the amount remaining, decay constant and age of a sample from N = N₀e^(−λt). - [The Photoelectric Effect](https://physicstuff.com/modern-physics/photoelectric-effect): Einstein's Nobel Prize experiment visualised — watch photons eject electrons from a metal plate and discover why frequency beats intensity every time. - [How Do Lasers Work?](https://physicstuff.com/modern-physics/how-do-lasers-work): Lasers amplify light through stimulated emission — explore the quantum mechanics of population inversion, optical cavities, and how the first laser was built in 1960. ### Fluid Mechanics - [Bernoulli's Principle Calculator: Fluid Dynamics, Pressure and Buoyancy](https://physicstuff.com/fluid-mechanics/bernoulli-principle-fluid-dynamics): Bernoulli's principle calculator and fluid dynamics simulator — model flow speed, pressure drop in a Venturi tube, and whether objects float or sink.